plasma-framework/layouts/layoutitem.h
2008-02-07 02:24:19 +00:00

183 lines
5.1 KiB
C++

/*
* Copyright 2007 by Matias Valdenegro T. <mvaldenegro@informatica.utem.cl>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU Library General Public License as
* published by the Free Software Foundation; either version 2, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details
*
* You should have received a copy of the GNU Library General Public
* License along with this program; if not, write to the
* Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#ifndef __LAYOUT_ITEM__
#define __LAYOUT_ITEM__
#include <QtCore/QRectF>
#include <QtCore/QSizeF>
#include <plasma/plasma_export.h>
class QGraphicsItem;
namespace Plasma
{
class Layout;
/**
* Base class for Plasma layout-managed items
*
* @author Matias Valdenegro T. <mvaldenegro@informatica.utem.cl>
*
* All layout-managed items should implement this class, but regular users just need to use
* Plasma::Widget and Plasma::Layout.
*/
class PLASMA_EXPORT LayoutItem
{
public:
/**
* Constructor.
*/
explicit LayoutItem();
/**
* Virtual Destructor.
*/
virtual ~LayoutItem();
/**
* Returns a bitmask with the directions that this Item can be expanded.
*/
virtual Qt::Orientations expandingDirections() const = 0;
/**
* Returns the minimum size of this Item and it's contents.
*/
virtual QSizeF minimumSize() const = 0;
/**
* Returns the maximum size of this Item.
*/
virtual QSizeF maximumSize() const = 0;
/**
* Returns true whatever this Item can use height-for-width layout management,
* false otherwise.
*/
virtual bool hasHeightForWidth() const;
/**
* Returns the corresponding height for a given width.
* @param w Width
*/
virtual qreal heightForWidth(qreal w) const;
/**
* Returns true whatever this Item can use width-for-height layout management,
* false otherwise.
*/
virtual bool hasWidthForHeight() const;
/**
* Returns the corresponding width for a given height.
* @param h Height
*/
virtual qreal widthForHeight(qreal h) const;
/**
* Returns the geometry of this Item.
*/
virtual QRectF geometry() const = 0;
/**
* Sets the geometry of this Item.
*/
virtual void setGeometry(const QRectF& geometry) = 0;
/**
* Updates the layouting of the item without first changing its geometry.
* Calling this may result in a geometry change, but may not, depending
* on the managing layout if any.
*/
virtual void updateGeometry() = 0;
/**
* Returns the most appropriate size of this Item to hold whatever contents it has.
*/
virtual QSizeF sizeHint() const = 0;
/**
* Sets the layout that will manage children items. The LayoutItem
* takes ownership of the layout from that point forward, unless
* unsetLayout() is called.
*
* @param layout The Layout that this LayoutItem will be managed by.
*/
void setLayout(Layout* layout);
/**
* Resets the layout that will manage children items to no layout.
* Note that the caller of this method must alert any items managed
* by the layout of this change if necessary. Primarily, this should
* only be used from the dtors of LayoutItem subclasses.
*/
void unsetLayout();
/**
* @return the layout this item is currently associated with.
*/
Layout* layout() const;
/**
* Sets the layout that manages this item's geometry
*
* @param layout the layout that manage this item's geometry
**/
void setManagingLayout(Layout* layout);
/**
* Resets the layout that manges this item's geometry if it is the
* currently associated layout
*
* @param layout to unset
**/
void unsetManagingLayout(Layout* layout);
/**
* @return the layout that manages this item's geometry, or 0 if none
**/
Layout* managingLayout() const;
/**
* Returns the graphics item associated with this layout item or 0
* if there is no associated graphics item.
*
* The default implementation returns 0.
*/
virtual QGraphicsItem* graphicsItem();
protected:
/**
* Reimplement to respond to a change in managing layout
*/
virtual void managingLayoutChanged();
private:
class Private;
Private *const d;
};
}
#endif /* __LAYOUT_ITEM__ */